[turbofan] Add AllocateHeapNumberStub to avoid runtime call.

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index 3e4f3e7361d4af78c7c5dc6ffeda82ff2b3fd1d3..5d02e84ebd9043d17185e8e18d094c2636bdb516 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -33,6 +33,7 @@ class PlatformInterfaceDescriptor;
   V(CallConstruct)                            \
   V(RegExpConstructResult)                    \
   V(TransitionElementsKind)                   \
+  V(AllocateHeapNumber)                       \
   V(ArrayConstructorConstantArgCount)         \
   V(ArrayConstructor)                         \
   V(InternalArrayConstructorConstantArgCount) \
@@ -346,6 +347,12 @@ class TransitionElementsKindDescriptor : public CallInterfaceDescriptor {
 };
 
 
+class AllocateHeapNumberDescriptor : public CallInterfaceDescriptor {
+ public:
+  DECLARE_DESCRIPTOR(AllocateHeapNumberDescriptor, CallInterfaceDescriptor)
+};
+
+
 class ArrayConstructorConstantArgCountDescriptor
     : public CallInterfaceDescriptor {
  public: